java 如何使用java中的正则表达式捕获多行模式?
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How can I capture a multiline pattern using a regular expressions in java?
提问by lampShade
I have a text file that I need to parse using regular expressions. The text that I need to capture is in multiline groups like this:
我有一个需要使用正则表达式解析的文本文件。我需要捕获的文本在多行组中,如下所示:
truck
zDoug
Doug's house
(123) 456-7890
[email protected]
30
61234.56
8/10/2003
vehicle
eRob
Rob's house
(987) 654-3210
[email protected]
For this example I need to capture truck followed by the next seven lines.In other words, in this "block" I have 8 groups. This is what I've tried but it will not capture the next line:
对于这个例子,我需要捕获卡车,然后是接下来的七行。换句话说,在这个“块”中,我有 8 个组。这是我尝试过的,但它不会捕获下一行:
(truck)\n(\w).
NOTE: I'm using the program RegExrto test my regex before I port it to Java.
注意:在将其移植到 Java 之前,我正在使用程序RegExr来测试我的正则表达式。
采纳答案by Alan Moore
(?m)^truck(?:(?:\r\n|[\r\n]).+$)*
This assumes the whole text has been read into a single string (i.e., you're not reading a file line-by-line), but it doesn'tassume the line separator is always \n
, as your code does. At the minimum you should allow for \r\n
and \r
as well, which is what (?:\r\n|[\r\n])
does. But it still matches only oneseparator, so the match stops before the double line separator at the end of the block.
这假定整个文本已被读入单个字符串(即,您不是逐行读取文件),但它并不假定行分隔符始终为\n
,就像您的代码所做的那样。至少,您应该允许\r\n
并且\r
也如此,这就是这样(?:\r\n|[\r\n])
做的。但它仍然只匹配一个分隔符,因此匹配在块末尾的双行分隔符之前停止。
Once you've matched a block of data, you can split it on the line separators to get the individual lines. Here's an example:
一旦匹配了一个数据块,您就可以在行分隔符上将其拆分以获取各个行。下面是一个例子:
Pattern p0 = Pattern.compile("(?m)^truck(?:(?:\r\n|[\r\n]).+$)*");
Matcher m = p0.matcher(data);
while (m.find())
{
String fullMatch = m.group();
int n = 0;
for (String s : fullMatch.split("\r\n|[\r\n]"))
{
System.out.printf("line %d: %s%n", n++, s);
}
}
output:
输出:
line 0: truck line 1: zDoug line 2: Doug's house line 3: (123) 456-7890 line 4: [email protected] line 5: 30 line 6: 61234.56 line 7: 8/10/2003
I'm also assuming each line of data contains at least one character, and that the blank lines between data block are really empty--i.e., no spaces, TABs, or other invisible characters.
我还假设每一行数据至少包含一个字符,并且数据块之间的空行实际上是空的——即,没有空格、制表符或其他不可见字符。
(BTW: To test that regex in RegExr, remove the (?m)
and check the multiline
box instead. RegExr is powered by ActionScript, so the rules are a little different. For a Java-powered regex tester, check out RegexPlanet.)
(顺便说一句:要在 RegExr 中测试该正则表达式,请删除(?m)
并选中该multiline
框。RegExr 由 ActionScript 提供支持,因此规则略有不同。对于Java 支持的正则表达式测试人员,请查看RegexPlanet。)
回答by Sergei
this pattern should work ((.*|\n)*)
这种模式应该有效 ((.*|\n)*)
回答by mazaneicha
I think that in order to span multiple lines your Pattern should be compiled in DOTALL mode, something like
我认为为了跨越多行你的 Pattern 应该在 DOTALL 模式下编译,比如
Pattern p = Pattern.compile("truck\n(.*\n){7}", Pattern.DOTALL);